However, at next week's Murrayfield Sevens Colin and Mike are likely to be playing in tandem at half-back.
"I am likely to start at fly-half, but either I, or Max Evans, can play scrum-half if we have to," Mike says in today's Scotland on Sunday. "I'd like to think that Budgie [Gregor] and I are pretty much interchangeable on the pitch. I think Budgie is Scotland's all-time top-scorer in sevens, and Ben [Cairns] also played last year. For the first time this season everyone in the team will have played international sevens, and that experience is priceless.
"Our aim for the last few tournaments has been to get to the cup quarter-finals. For the Murrayfield tournament, we are aiming a little higher after achieving our previous goals, and going for a place in the cup semi-finals."
At just 11 st and 5ft 8in, Mike is accustomed to comments about being too small for the pro game, but anyone who has seen him in action for Glasgow Hawks knows he more than tackles his weight.
"I've had that size thing hanging over me for years," says Mike who has signed a full-time pro contract with the Warriors. "It started when I played at school in the centre at Dollar Academy alongside Graeme Morrison, who is six foot three.
"I think that sevens helps me cope with that, because you are playing against professionals from New Zealand, Australia and South Africa and, in my case, it helps me develop my one-on-one defensive skills. You really don't have anywhere to hide on the sevens field: you have to front up and be physical."